This invention generally relates to portable battery-powered electronic devices. In particular, the invention relates to such battery-powered equipment used to monitor patients during transport in a hospital or other patient care setting.
Pedal mechanisms for operating the brake and directional wheel lock of standard lever-operated caster wheels, such as those installed on ultrasound systems, have traditionally been cumbersome to operate, requiring that the pedal(s) be pressed from awkward angles. They have also often required the pedal to be lifted by the toe to get back into its original position. This has caused complaints from many operators and especially females using open sandal-like footwear. In addition, in earlier solutions it has been difficult to visually determine which of three positionsxe2x80x94namely, directionally locked, free swivel or brakedxe2x80x94the pedal is in. There have also been complaints about the user interface and that operation of the mechanisms is not very intuitive.
There is a need for the mechanical design of a cost-effective pushxe2x80x94push pedal mechanism for converting the vertical motion of two different pedals to the horizontal activation of the lever of a conventional caster wheel assembly, which design is such that the position of the pedals indicates which of three possible states the pedal mechanism is in.
The present invention is directed to an improved pedal mechanism for operating the brake and directional wheel lock of standard lever-operated caster wheels or other actuatable mechanical devices. Although the invention is disclosed in the context of an ultrasound scanner, the invention has application to other scanners and even other types of equipment having an actuatable mechanical device suited for control via pedal operation. Nor is the pedal mechanism of the invention limited in its application to mechanical devices that are actuated by means of a lever.
In accordance with the preferred embodiment disclosed herein, a scanner or other system has an actuator, a mechanical device having three states corresponding to three respective positions of the actuator, and a pedal mechanism. The pedal mechanism comprises: a support structure; first and second slotted arms pivotably mounted to the support structure; first and second latches respectively pivotably mounted to the first and second arms; a pivot part pivotably mounted to the support structure; and a mechanism for converting pivoting of the pivot part into movement of the actuator, e.g., swinging of a lever. The pivot part has first and second extensions which extend in generally opposite directions and which respectively protrude through the slots in the first and second arms. The pedal arms, latches and pivot part cooperate to enable the position of the actuator to be controlled by depressing one pedal at a time. In particular, the pedal mechanism comprises first and second pedals and is designed to control the position of the actuator in response to depressions of the pedals in accordance with the following sequence: (1) the actuator is moved from a second position to a first position in response to depression of the first pedal while the actuator is in the second position; the actuator is moved from the first position to the second position in response to depression of the second pedal while the actuator is in the first position; the actuator is moved from the second position to the third position in response to depression of the second pedal while the actuator is in the second position; and the actuator is moved from the third position to the second position in response to depression of the first pedal while the actuator is in the third position.
The pedal mechanism disclosed herein offers an easy-to-use user interface, supplying a clear visual information concerning which of the three positions the mechanism and casters are in. It allows for an ergonomically good operation with the line of force close to vertical and without the need for any pedals to be lifted by the system operator using his/her toe. The pedals are easily accessible and there is little risk of putting the mechanism in an unwanted position.
The pedal mechanism itself can be manufactured from cheap materials and components. Manufacture involves some sheet bending, typically in semi-automated machines, but for series production these costs too will be low. The design in accordance with the preferred embodiment allows for generous manufacturing tolerances and requires few welds, so that little heat distortion occurs. The cost of manufacture will be competitive with simpler conventional pedal mechanisms which offer less functionality and fewer features than does the invention. The pedal mechanism disclosed herein is also compact and with a form factor and design to avoid the risk of the operator""s toe kicking into the mechanism while transporting the system.
Other aspects of the invention are disclosed and claimed below.